Micro-fluid ejection devices have continued to find application in a variety of fields including, but not limited to, ink jet printing, micro-fluid heat transfer, micro-biological preparations, pharmaceutical delivery and the like. As higher quality ejection devices are produced, it becomes increasingly important to protect the orifice plates on the ejection heads during handling, storage, and shipping of the devices so that contamination of fluids or plugging of orifices does not occur. Conventionally, cover tapes are applied to the orifice plates and are removed prior to use of the devices. The cover tapes should be sufficient to adequately seal the orifices to prevent evaporation and intermixing of fluids and should be constructed of materials that are resistant to and do not contaminate the fluids. Removal of the cover tapes should also not leave undesirable residue on the orifice plate.
Pressure sensitive adhesive (PSA) tapes have been used as cover tapes. The PSA tapes are generally constructed of a base film with an acrylate based PSA layer used to seal the orifices on the orifice plate. The base film is typically made of polyethylene terephthalate commonly referred to as polyester (PET) or polyvinyl chloride (PVC).
The acrylic PSA layer is a polymer that can swell (absorb liquids). Accordingly, the PSA layer may be viewed as a polymeric sponge above its glass transition temperature. Typically, the glass transition temperature of acrylic PSA's is at or below about 0° C. Therefore, at any temperature above the glass transition temperature, the adhesive has a high propensity to swell and to flow. During micro-fluid ejection head manufacturing, the ejection head is at or above room temperature. Hence, the PSA layer attached to the orifice plate is constantly absorbing fluid components until an equilibrium point is reached and the adhesive is saturated. Once saturated at the elevated temperature, the acrylic PSA material can flow into the nozzle holes and plug or clog the nozzle holes.
Another disadvantage of an acrylic based PSA cover tape is that a cohesive strength of the PSA is weak with respect to the base film. When the tape is removed from the nozzle plate, the adhesive may be left in the nozzle holes causing a clogged nozzle and/or misdirected fluid. As the nozzle holes get smaller, it is harder to remove PSA material that has swelled in the nozzle holes.
Accordingly, there is a need for improved orifice plate protection devices containing improved adhesives that reduce fluid leakage, fluid evaporation, contamination, and fluid intermixing, and that are easily removable from the orifice plate while minimizing the amount of unwanted residue left on the orifice plate. There is also a need for improved methods for sealing the nozzle holes of an orifice plate for a micro-fluid ejection head.
With regard to the foregoing, the disclosure provides an orifice plate sealing tape for an orifice plate of a micro-fluid ejection device. The sealing tape includes a radiation curable adhesive for application adjacent to a surface of the orifice plate and a flexible polymeric backing film in adhesive contact with the adhesive. The adhesive is curable in a pattern sufficient to seal adjacent to nozzle holes in the orifice plate and to enhance removal of the backing film and adhesive from the orifice plate prior to use of the micro-fluid ejection device.
In another embodiment, there is provided a method of sealing an orifice plate for a micro-fluid ejection device to prevent leakage and evaporation of fluid from the device during handling and shipping. The method includes applying a radiation curable adhesive and backing film to a surface of the orifice plate. The adhesive is cured in a pattern sufficient to seal adjacent to nozzle holes in the orifice plate and to enhance removal of the backing film and adhesive from the orifice plate prior to use of the micro-fluid ejection device.
In yet another embodiment, there is provided a method for enhancing sealing tape and adhesive removal from an orifice plate for a micro-fluid ejection device. The method includes applying a patterned adhesive and backing film to a surface of the orifice plate. The adhesive and film are exposed to radiation sufficient to at least partially cure the adhesive.
Another exemplary embodiment provides a micro-fluid ejection head attached to a fluid cartridge body. The micro-fluid ejection head has an orifice plate with a backing film and radiation curable adhesive applied to a surface of the office plate for sealing nozzle holes in the orifice plate. The adhesive is curable in a pattern sufficient to seal adjacent to nozzle holes in the orifice plate and to enhance removal of the backing film and adhesive from the orifice plate prior to use of the micro-fluid ejection head.
Advantages of exemplary embodiments described herein include, but are not limited to, an ability to adjust the amount of adhesion between a nozzle plate sealing tape and a nozzle plate of a fluid ejection device. Another advantage is that the tape may be removed from the nozzle plate with a minimum of residue left on the nozzle plate and in nozzle holes of the nozzle plate. Yet another advantage is that the cured adhesive may have less affinity for the fluids ejected through the nozzle holes and thus may exhibit less deterioration over time thereby improving the sealing capabilities of the tape.